Video games are cool. Whereas once, gaming was purely for childrens and geeks, it's now a genuine mainstream leisure activity. And if there's one thing the gaming industry knows about, it's stickiness. The best video games are exceptionally sticky, purveying a "just one more go" culture that hooks even the most casual gamers into lengthy goggled-eyed console sessions.

But it's not just about consoles and PCs. There's an ever increasing number of web-based games, using technology such as Flash, Java and shockwave. Sometimes they're created for fun, but more often they're used as marketing tools. Something to pull users in, persuade them to return regularly, and be passed on to their friends.

There have already been many banners ad games, including the Hewlett-Packard's semi legendary Pong banner. Viral games have had plenty of hype in the last year too, as marketing types fall over themselves to jump in the viral bandwagon. And there's even sites full of games, from the multimedia thrills of shockwave.com through to the purely text-based quizzed on e-mode.

Web based games are fun to produce, but how can you ensure that yours is truly sticky? Although there's no hard and fast set of rules, there are underlying principles that should be born in mind. We've talked to the experts to pull together these ten hot tips, as well as the best examples online. Game on.

1 - Keep it simple

Whatever technology you're using to create your game, a low file size is a necessity. If users are left twiddling their thumbs while your mini-masterpiece downloads, they'l lose patience sooner rather than after. "If you're delivering a 30-second game experience, it's disapointing if you're forced to wait ten minutes for it download first," points out Deepend multimedia designer Pete Everett.
For this reason, ditch any thoughts of whizzy textures or complex multi-layered backgrounds. But don't worry: "Constraint often breeds creativity" says Everett. "The game are often more playable as a result."

Micro Jet Racer: very addictive, but just 110k.
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2 - Get old-skool

You're not the first game designer working to a tight file size. Look to classic arcade for inspiration: Space Invaders, Pong, Breakout, Frogger...whatever. "At the time, they had even more technology constraints than we do nowadays," says JohnJohn's Benoit Viellefon. "And yet developpers were still able to create some really good addictive games."
If you're creating a simple branded game for a corporate client , it's worth considering whether you can adapt a classic game to your own ends. And there's another advantage too: "you don't have to explain the rules to the players," says Viellefon. "They already know how to play."

3 - Know your audience

Before rolling out the hard-core gaming thrills, stop to think about the audience for your game. Will they be experienced gamers, or complete novices? It could make big difference, especially if you'r working on a new medium.
"When you're creating games for the Web, mobile phones or interactive TV, you could be dealing with people who've never played a computer game before," says David Streek, design director at Deepend. "You should try to put yourself in the mind of the intended audience, as different consumers react to games in different ways."

4 - Think viral

If your game is good, people will be scrambling to pass it on to their mates. Who in turn will pass it to their mates. And so on. And while they might copy and paste the URL into an email, why not make it easy for them to alert their friends to your game's existence?
All it takes is a simple automated form, enabling people to enter a bunch of email addresses to notify about the game. It's relatively easy to factor in, but it means your game potential for viral popularity will be immense. Of course, if you've done a standalone promotional game that's under 500k, people will be able to email the whole thing...

5 - Know your audio

Sound is absolutely crucial to a great Web-based game. Yes, you have to work within the strict file size limitations we talked about earlier, but that shouldn't mean you skimp on your audio. "The quality of the sound effects and music is really important," says Benoit Viellefon.
"Imagine playing a game with the sound turned off. It's not half as much fun. Good sound affects make the game exciting, and the right music will keep people playing. You have to get on their nerves!"

6 - Don't be cruel

Getting the difficulty right is one of the most important things about creating a genius Web-based game. Too easy, and users will get bored. Too hard, and they'll flee screaming for the comfort of their Game Boys. "You have to make the game quite hard to win," says Benoit Viellefon. "Make it challenging for people , otherwise it's no fun. But don't put them off."
The key is user testing. Get your friends, family and any other casual acquaintances' pets to play your game before it goes live. Use that process to fine-tune the difficulty level.

7 - Choose your tech

Java, Shockwave, Flash, Director...There are various technologies that you can create Web-based game in - each with their own pros and cons. Flash and Shockwave tend to be better choices if you're starting from scratch. "It's very difficult to write a good Java game if you're not an expert," says Benoit Viellefon. "It can also be expensive. Flash is a cheaper alternative, and it's easier to learn too. But I would say that, as I'm not a Java expert!"
Your best course of action, in other words, is to go with what you know.

8 - Test yourself

Just like in the proper games industry, testing is a vital part of the process. "You have to test your game on as many platforms , in as many browsers and on as many different spec machines as you can," says Pete Everett. Not everyone has a 1Ghz processor, and a game that runs like a dream on your development PC might run like a dog on a three years old Macintosh."
This is particularly true if you're planing to set a limit on your game, making users compete against the clock. "Your game should not be easier to complete if you are playing on a faster machine!" says Everett.

9 - Know the score

High-score tables are a great feature. They enable users to compare their ratings against everyone else, and can provide sufficient motivation for them to keep coming back and bettering their previous efforts. Emarketeers designer Stephen Folkes worked on a Web-based game that offers prizes for players who top the high-score tables. "Visitors are returning again and again to beat the score, to get their name on the front of the site and a prize in the post." he says. Proven stickiness.

10 - Be original

This may seem like a direct contradiction to point two but bear with us. It's all very well looking to existing game for inspiration, but you'll have to use them in original context. "It's a natural process to use the games you loved to influence your own design," says Davis Streek. "But where possible, use them in an original mix with a different objective."
He cites the example of Sonic the Hedgehog and Super Mario World. "They're actually very similar in terms of their format, but they combine these similar elements in very differents ways, and play at a different pace."